Reactor control rod operating system



Dec. 12, 1961 G. MILLER 3,012,542

REACTOR CONTROL ROD OPERATING SYSTEM Filed Nov. 7, 1958 5/ 29 W 24* N FIG.4.

FIG. I.

INVENTOR. W Em GEORGE MILLER J L BY 3/. wag a W ATTORNEYS:

United States Patent,

3,012,542 REACTOR CONTROL ROD OPERATING SYSTEM George Miller, Cornwells Heights, Pa., assignor to the United States of America as represented by the Secretary of the Army Filed Nov. 7, 1958, Ser. No. 772,640 2 Claims. (Cl. 12140) (Granted under Title 35, U.S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to systems for operating the control rods of reactors, and more particularly to an im-.

proved system which functions to move such reactor rods mechanically during normal operation and by catapultic action in case of emergency.

In the operation of a reactor, it is sometimes desirable that the control rods be moved more rapidly than is possible with the mechanical systems heretofore used for this purpose. In accordance with the present invention, this result is achieved by means of catapultic action. To this end, there is interposed between the reactor rods and the mechanical drive system a catapult which takes over control of the rods in response to the firing of an explosive cartridge.

The invention will be better understood from the following description when considered in connection with the accompanying drawings and its scope is indicated by the appended claims.

Referring to the drawings:

FIG. 1 illustrates the invention as utilized to operate the rods from a room beneath the reactor pile,

FIG. 2 is a section taken on the line 22 of FIG. 1,

FIG. 3 is a section taken on the line 33 of FIG. 1,

FIG. 4 is a sectional view illustrating a mechanism by which control of the reactor rods is transferred from the mechanical drive system to the catapult in response to the firing of an explosive cartridge,

FIG. 5 is a section taken on the line 5-5 of FIG. 1.

FIGS. 1 and 2 show a pair of reactor control rods and 11 which are mounted on a crosshead 12 and extend upwardly into a pile (not shown). The crosshead 12 is movable within a casing 13 and has threaded into it a tube 14 (FIGS. 1 and 4) which has at its upper end a plurality of firing chambers 15.

A threaded tube 16 surrounds the tube 14, is arranged to be coupled to the crosshead 12 by a latch 17 having a hook-end 40, and another end 41, and a pivot point 42, and is driven by a motor 18 through gear 19 and power nut 20 to move the rods into and out of the pile in a conventional manner.

A piston 21 (FIG. 4) is movable within the tube 14, is biased to its illustrated position by a spring 22, and has pivoted to it a link 23. The link 23 is pivoted to the lower end of the latch 17 which is pivoted to the crosshead 12 at a point 42 intermediate its ends. With this arrangement, a downward movement of the member 21 disengages the clutch 17 from the threaded pipe 16. While only one latch 17 is shown in FIG. 4, it is apparent that a plurality of such latches all operated by the member 21 may be provided if desired.

At the bottom of the casing 13 is a decelerating device 3,012,542 Patented Dec. 12., 1961 in the form of an oil buifer which includes a cylinder 24, a piston 25 and a piston rod 26. The cylinder 24 communicates with a reservoir 27 through an orifice 28 and has tapered grooves 29 on its inner periphery through which oil is forced from the cylinder to the reservoir as the piston descends. A spring 30 extending from the lower end of the cylinder 24 up into a hollow part of the rod 26 normally maintains the piston and rod in their illustrated positions.

Features of the control rod operating system are (1) upper and lower limit switches 31 and 32 which function to deenengize the motor 18 when the rods 10' and 11 reach the limits of their travel and (2) a latch 33 which is biased to its illustrated position by a spring 34 for automatically locking the crosshead 12 at the lower limit of its travel and is operable to release the crosshead when a solenoid 35 is energized.

During normal operation of the reactor control rod operating system, the rods are moved to and fro in a conventional manner by the motor which is fixed to the casing 13. The cartridges located in the firing chambers 15 may be fired manually or automatically by a radiation meter, a temperature detector or the like. When one of the cartridges is fired, the piston 21 is driven downward compressing the spring 22 and operating the catch 17 to release the tube 14 from the threaded tube 16. Thereupon the crosshead 12 and everything supported by it is catapulted downward. Near the end of this downward movement, the rod 36 of a valve 37 seated in the member 21 engages the end of the piston rod 26 opening the valve 37 and venting the gas pressure within the tube 14. Thereafter, the downward movement of the crosshead 12 and rods 10 and 11 is cushioned by the oil buffer as previously indicated and the crosshead is locked in position by the latch 33.

Further operation of the system is initiated by energizing the solenoid 35 which operates the catch 33 to release the crosshead 12 whereupon the spring 30 pushes the crosshead within the lower limit of its normal travel. Tube 16 is mechanically run down and latches onto the crosshead 12. In this way, operation of the system is readily restored after the firing of each of the cartridges. It is to be understood that the cartridges utilized are preferably of the electrical primer type and that any desired number of firing chambers may be provided. While only two operating rods are shown, it is apparent that any desired number may be operated by the above described system. It should also be understood, rods can be injected into the pile by some mechanism simply by upending and changing position of rods.

I claim:

1. In a mechanism for moving a support by a force which is the resultant sum of gravity and a gas pressure, the combinationtherewith of an outer tubular member having an external flange at its lower end, an inner tubular member reciprocable within said outer tubular member and fixed to said support, a piston movable in said inner tubular member upon the application of a gas pressure through said inner tubular member, means biasing said piston to a predetermined position of rest in said inner tubular member, a latch pivoted to said support and arranged to engage said flange for coupling said outer tubular member to said support, and a link pivoted at one end to said latch and at the other end to said piston, said link having a length such that said latch engages said References Cited in the file of this patent UNITED STATES PATENTS Beach Aug. 23, 1949 Lane et al. May 12, 1959 1 0 4 FOREIGN PATENTS 795,565 7 Great Britain May 28, 1958 OTHER REFERENCES IDO-24020, Engineering Test Reactor, USAEC report dated July 1956, pages 96-104, 126, 130.

Nucleonics, vol. 15 (July 1957), insert (both sides) between pages 52 and 53. 

